Optical power for electronic switches

ABSTRACT

Various embodiments provide a laser power beaming system that delivers power via high intensity light, such as from a laser, using either power over fiber or free space power to isolate (or eliminate) high frequency noise and electromagnetic interference (EMI) due to, for example, switching. Damage or other harms from the EMI may be prevented. The opto-isolated power may be delivered from a remote source, or within a switched device, such as a variable frequency drive (VFD), itself.

BACKGROUND Technical Field

The present disclosure generally relates to providing optical power forisolation of electric components.

Description of the Related Art

Several problems are well understood in the operation of inverters(including those that drive Variable Frequency Drives, aka VFDs) andother devices that vary the input frequency and voltage supplied toelectric induction motors. These problems include EMI (ElectromagneticInterference), switching speed, size, and other factors. Of particularconcern is Electromagnetic Interference.

Electromagnetic Interference (EMI) is a disturbance generated by anexternal source that affects an electrical circuit by electromagneticinduction, electrostatic coupling, or conduction. Such a disturbancefrom an external source may degrade or stop the performance of thecircuit. With respect to a data path, these EMI disturbances can rangefrom an increase in error rate to a total loss of the data. Notably, EMIdisturbances may be man-made or of natural origin. Changing electricalcurrents and voltages that can cause EMI includes, by way of exampleonly, and not by way of limitation: ignition systems, cellular networkof mobile phones, arc discharges, lightning, solar flares, and auroras.

Problems with EMI occur in a broad cross-section of use cases andapplications. Problems associated with current VFD designs occur whenconductive elements (copper for instance) connect sensitive or criticaldevices, such as solid state and other switches. Some of the issuescreated by inverter (e.g., VFD) EMI in inductive motors include (but arenot limited to) insulation breakdown, premature motor failure, motoroverheating, potential voltage and current spike damage to sensitivecontrol equipment or other unrelated equipment on the same electricalpower circuit, and damage to high performance III-V semiconductorswitches.

EMI also can have significant impact on the internal function andcomponents within the VFD. Transformers and other components haveinherent capacitance, which can couple electrical noise from oneelectrical line to another.

Significant research and development has been applied to the increase ofhigh switching speeds applied to inverter design. High switching speedsdecrease harmonics and improve output motor performance. Some of thesebenefits include lowered motor losses, reduced motor heating, reducedoutput noise, and higher maximum motor speed. However high switchingspeeds can be limited by the materials used in IGBTs (Insulated-GateBipolar Transistors). Hence the recent development push to introducewide bandgap (including III-V) materials to inverter design.

Wide Band Gap Semiconductor (WBGS) switches have several benefits oversilicon. Those include greater efficiency, and reduced cost, size, andweight. However, inverter switches made from Wide Band GapSemiconductors (WBGS) are susceptible to EMI.

Using SiC (silicon carbide) and GaN (gallium nitride) materials inswitches (such as IGBTs) enables higher speed, but devices made usingthese materials may be more voltage sensitive than traditional (mainlysilicon) devices. As an example, a silicon device might operate at 10Vbut be robust against input voltages up to 30V. But in this example, aGaN device might need 5V but only be robust against inputs up to 6V. Theswitching harmonics and EMI can potentially create brief voltages thatare too high for these (SiC, GaN) devices.

BRIEF SUMMARY

The present disclosure is directed to a power beaming system, either viaoptical fiber or free space, that provides electrically isolated powerin a small form factor. Electrical power may be delivered optically andprojected as light from a high intensity light source, such as a laser,to a receiver (most often including one or more photovoltaic cells) thatconverts the light back into electricity. Power transmitted via anoptical element is generally immune to, and does not couple or generateElectromagnetic Interference (EMI).

In one or more embodiments, a wireless optical power system includes oneor more laser transmitters, one or more photoreceptor receivers, athermal management system that may be integrated within the laser powertransmitter or may also be a separate thermal management system in theinverter or power receiver, one or more control systems for thetransmitter and the receiver, and a light-conductive element (fiber,light tube, or air, for example) in between the transmitter andreceiver.

In some embodiments, a device includes a plurality of electricalswitching elements, a plurality of drivers, and a converter. Theplurality of drivers are electrically coupled to the plurality ofelectrical switching elements, and the plurality of drivers areconfigured to change operating states of the plurality of electricalswitching elements. The converter includes a plurality of photovoltaic(PV) modules configured to receive a plurality of light beams andconvert the plurality of light beams into electrical signals for theplurality of drivers. The plurality of PV modules being electricallyisolated from each other.

In another aspect of some embodiments, the device further includes alaser power transmitter configured to receive an electrical powersignal, and transmit the plurality of light beams in response toreceiving the electrical power signal, the converter receives theplurality of light beams from the laser power transmitter. In stillanother aspect of some embodiments, the plurality of light beams haveelectrical characteristics corresponding to the electrical power signal.In yet another aspect of some embodiments, the device further includes atransmission medium, the plurality of light beams being transmitted fromthe laser power transmitter, through the transmission medium, and to theconverter. In some embodiments, the transmission medium is an opticalfiber. In another aspect of some embodiments, the laser powertransmitter includes optics configured to shape, split, reflect, orrefract the plurality of light beams. In yet another aspect of someembodiments, each of the plurality of PV modules includes at least onephotovoltaic cell configured to convert light into electricity, and thedevice further includes a plurality of power management and distributionmodules electrically coupled to the plurality of PV modules.

In another aspect of one or more embodiments, the device furtherincludes a laser power transmitter and an optical splitter. The laserpower transmitter is configured to receive an electrical power signal,and transmit a light beam in response to receiving the electrical powersignal. The optical splitter is configured to receive the transmittedlight beam, and split the transmitted light beam into the plurality oflight beams. In still another aspect of one or more embodiments, thedevice further includes mirrors configured to redirect the plurality oflight beams towards the plurality of PV modules. In yet another aspectof one or more embodiments, the device further includes an opticalelement configured to collimate the transmitted light beam. In anotheraspect of the device, the optical splitter is configured to collimatethe transmitted light beam. In still another aspect of the device, theoptical splitter is a pyramidal mirror.

Referring now to another aspect of some embodiments, the device furtherincludes a first substrate, a second substrate, and a third substrate.The first substrate includes a first PV module of the plurality of PVmodules that is positioned on the first substrate. The second substrateincludes a second PV module of the plurality of PV modules that ispositioned on the second substrate. The third substrate including thefirst substrate, the second substrate, and the optical splitter arepositioned on the third substrate. The first and second substratesextend in a first direction, and the third substrate extends in a thirddirection transverse to the first direction.

In another aspect of one or more embodiments, the device furtherincludes a controller, a multiplexer, a laser power transmitter, and ademultiplexer. The controller is configured to generate a plurality ofcontrol signals for the plurality of drivers. The multiplexer isconfigured to receive the plurality of control signals, and transmit acontrol signal of the plurality of control signals. The laser powertransmitter is configured to receive the control signal, and transmit alight beam in response to receiving the control signal. Additionally,the converter is configured to receive the first light beam from thelaser power transmitter, and convert the light beam into an electricalsignal. Furthermore, the demultiplexer is configured to receive theelectrical signal, and route the electrical signal to the plurality ofdrivers.

Referring now to still another embodiment, an optical power systemincludes a laser transmitter, a power receiver, and a non-conductiveoptical fiber cable. The laser transmitter is configured to emit a lightbeam. The power receiver includes two or more photovoltaic modulesconfigured to receive the light beam. The non-conductive optical fibercable includes one or more optical fibers. The optical fiber cable isconfigured to transmit the light beam from the laser transmitter to thetwo or more photovoltaic modules. The power receiver has two or morepower outputs that are electrically isolated from each other. In one ormore other embodiments of the optical power system, there is not aconductive path between the laser transmitter and the power receiver.

In one or more other embodiments, a power receiver includes a pluralityof photovoltaic (PV) receiver legs, wherein each PV receiver legincludes a PV module configured to convert an optical input to anelectrical output, and wherein each member of the plurality of PVreceiver legs is electrically isolated from each other member of theplurality.

In one or more embodiments of the power receiver, each PV moduleincludes at least one PV cell. In another embodiment of the powerreceiver, at least one PV module comprises a plurality of PV cells. Instill another embodiment, the power receiver further includes an opticalelement configured to: receive an incoming light beam; and direct atleast a portion of the received incoming light beam onto a member of theplurality of PV receiver legs. In yet another embodiment of the powerreceiver, the optical element includes a beam splitter configured todirect a portion of the incoming light beam onto each member of theplurality of PV receiver legs. In some embodiments of the powerreceiver, the optical element is further configured to collimate thedirected light beam. In other embodiments of the power receiver, theoptical element is further configured to reshape the incoming lightbeam.

In one or more embodiments, the power receiver further includes anoptical fiber configured to direct an optical input toward one or moremembers of the plurality of PV receiver legs. In some embodiments of thepower receiver, the plurality of PV receiver legs are mounted on acommon substrate. In other embodiments of the power receiver, the PVmodules of each member of the plurality of PV receiver legs are mountedon the common substrate. In still other embodiments of the powerreceiver, the PV modules of each member of the plurality of PV receiverlegs are mounted on a separate substrate, each separate substratepositioned at an oblique angle to the common substrate. In yet otherembodiments of the power receiver, at least one of the PV receiver legsincludes a power management and distribution (PMAD) component.

In another embodiment, the power transmission system includes a powerreceiver and a light source. The power receiver includes a plurality ofphotovoltaic (PV) receiver legs, wherein each PV receiver leg includes aPV module configured to convert an optical input to an electricaloutput, and wherein each member of the plurality of PV receiver legs iselectrically isolated from each other member of the plurality. The lightsource is configured to provide an optical input to the power receiver.In some embodiments, the power transmission system further includes atransmission element configured to conduct the optical input from thelight source to the power receiver. In other embodiments of the powertransmission system, the transmission element is an optical fiber. Instill other embodiments, the power transmission system further includesa multiplexer configured to encode a control signal into the opticalinput. In yet other embodiments, the power transmission system furtherincludes a controller configured to create the control signal forencoding by the multiplexer.

In some embodiments of the power transmission system, at least onemember of the plurality of PV receiver legs includes a demultiplexerconfigured to extract the encoded control signal from the electricaloutput of its PV module. In other embodiments of the power transmissionsystem, each member of the plurality of PV receiver legs includes ademultiplexer configured to extract the encoded control signal from theelectrical output of its PV module. In still other embodiments of thepower transmission system, each demultiplexer is configured to identifya portion of the encoded control signal that pertains to its own PVreceiver leg. In yet other embodiments, the power transmission systemfurther includes a driver for controlling an electrical component,wherein the driver is configured to receive the extracted control signalfrom the demultiplexer and to use the received control signal to drivethe electrical component.

In some embodiments, the electrical component is a switch. In anotheraspect of power transmission system, the power receiver and the lightsource are enclosed in a common housing. In still another aspect ofpower transmission system, the power receiver and the light source areseparated by a distance of less than one meter. In yet another aspect ofpower transmission system, the power receiver and the light source areseparated by a distance of more than five meters. In other aspects ofpower transmission system, the power receiver and the light source areseparated by a distance of more than one kilometer.

Referring now to a method of providing electrical power to a group ofelectrical components, the method includes: directing an optical powerbeam toward a plurality of photovoltaic (PV) receiver legs, each PVreceiver leg including a PV module and being associated with anelectrical component; and receiving the optical power beam at theplurality PV receiver legs, wherein each PV module of the plurality ofPV receiver legs (1) converts a portion of the optical power beam into alocal electrical output and (2) provides the local electrical output topower the electrical component associated with its PV receiver leg,wherein the electrical component associated with each PV receiver leg iselectrically isolated from electrical components associated with otherPV receiver legs.

In some embodiments, each PV module includes at least one PV cell. Inother embodiments, at least one PV module includes a plurality of PVcells. In still other embodiments, at least one electrical componentincludes a switch. In other embodiments, the method further includesmodulating the optical power beam to provide a control signal for theelectrical components. In yet other embodiments at least one PV receiverleg includes a demultiplexer. The method further includes: extractingthe control signal from the local electrical output using thedemultiplexer; and using the control signal to control the electricalcomponent.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar featuresor elements. The size and relative positions of features in the drawingsare not necessarily drawn to scale.

FIG. 1 is a laser power beaming system according to an embodimentdisclosed herein.

FIG. 2 is a laser power transmitter according to an embodiment disclosedherein.

FIG. 3 is a power receiver according to an embodiment disclosed herein.

FIG. 4 is a power receiver according to another embodiment disclosedherein.

FIG. 5 shows a laser light being split into separate beams according toan embodiment disclosed herein.

FIG. 6A shows receiver optics according to an embodiment disclosedherein.

FIG. 6B shows receiver optics according to another embodiment disclosedherein.

FIG. 7 shows a laser power transmitter and a power receiver according toanother embodiment disclosed herein.

FIG. 8A is a laser and a photovoltaic module according to an embodimentdisclosed herein.

FIG. 8B is a laser and a photovoltaic module according to anotherembodiment disclosed herein.

FIG. 9 shows a laser light being split into separate beams according toan embodiment disclosed herein.

FIG. 10A is a laser power beaming system with a single demultiplexeraccording to another embodiment disclosed herein.

FIG. 10B is a laser power beaming system with two demultiplexersaccording to another embodiment disclosed herein.

FIG. 11A is a driver and a switches according to an embodiment disclosedherein.

FIG. 11B is drivers and a switches according to another embodimentdisclosed herein.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various aspects of thedisclosed subject matter. However, the disclosed subject matter may bepracticed without these specific details. In some instances, well-knownstructures and methods of manufacturing light emitting devices, lightsensors, drivers, integrated circuits, and electrical components (e.g.,transistors, resistors, capacitors, switches, etc.) have not beendescribed in detail to avoid obscuring the descriptions of other aspectsof the present disclosure.

Unless the context requires otherwise, throughout the specification andclaims that follow, the word “comprise” and variations thereof, such as“comprises” and “comprising,” are to be construed in an open, inclusivesense, that is, as “including, but not limited to.”

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearance of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thespecification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more aspects of the presentdisclosure.

Prior to setting forth the embodiments however, it may be helpful to anunderstanding thereof to first set forth definitions of certain termsthat are used hereinafter.

Reference throughout the specification to integrated circuits isgenerally intended to include integrated circuit components built onsemiconducting or glass substrates, whether or not the components arecoupled together into a circuit or able to be interconnected.

The term power beam is used, in all its grammatical forms, throughoutthe present disclosure and claims to refer to a high-flux lighttransmission that may include a field of light, that may be generallydirectional, that may be arranged for steering/aiming to a suitablereceiver. The power beams discussed in the present disclosure includebeams formed by high-flux laser diodes or other like sources sufficientto deliver a desirable level of power to a remote receiver withoutpassing the power over a conventional electrical conduit such as wire.

In the present disclosure, the term “light,” when used as part of alight-based transmitter or a light-based receiver refers to atransmitter or receiver arranged to produce or capture, as the case maybe, electromagnetic radiation that falls within the range of frequenciesthat can be directed (e.g., reflected, refracted, filtered, absorbed,captured, and the like) by optical or quasi-optical elements, and whichis defined in the electromagnetic spectrum spanning from extremely lowfrequencies (ELF) through gamma rays, and which includes at leastultraviolet light, visible light, long-, mid- and short-wavelengthinfrared light, terahertz radiation, millimeter waves, microwaves, othervisible and invisible light, light beams, and light transmitted within afiber. A “beam” of light, as that term is used herein, may include botha beam transmitted through free space and a guided beam such as onetransmitted through an optical fiber.

In the present disclosure, the term “optics” may be used to identifyoptical elements which may shape, split, reflect, refract, or otherwisemodify a light beam. When present in an embodiment, “optics” mayidentify a single component or multiple components.

It is noted that the dimensions set forth herein are provided asexamples. Other dimensions are envisioned for this embodiment and allother embodiments of this application.

As discussed above, the operation of inverters, including those thatdrive VFDs, causes problems such as Electromagnetic Interference.Electromagnetic Interference can have significant impact on the internalfunction and components within a VFD. Transformers have inherentcapacitance, which can couple electrical noise from one electrical lineto another.

A transformer with four separate windings is a design that is generallysomewhat large (on the order of four inches on a side). Due to theproximity of the windings to each other, coupling between separate legsof the transformer can occur, which creates EMI/fluctuations that canpropagate back through the electronic supply to other powered devices inthe same electrical grid, and may also cause problems in the VFD motoritself.

The (normally four) separate legs are floating at different voltagesrelative to each other. These legs may be connected to four separatewindings on a transformer, each winding going to a different leg: threefor the high voltage ends of the device, and one for the ground voltageend which is common to all three legs of the device. The switching noisemay propagate through the windings and to the other legs, as well asback up the input power line.

Some of the methods that are currently used to reduce the impact ofthese problems include creating sufficient distance between internalcomponents to reduce potential inductive coupling between conductiveelements, upstream and downstream “filtering” electronics to reduce EMIimpacts, physically placing the EMI producing elements a significantdistance from the load, special considerations to the cable lengths toand from the load, special construction of motors to reduce bearingdamage from EMI, and cable shielding and shielding of components.

Although the foregoing modifications mitigate the EMI issues, themodifications do not sufficiently solve the problem of EMI and some evenintroduce new problems and design challenges.

The present disclosure generally relates to power beaming. Moreparticularly, but not exclusively, the present disclosure relates toproviding optically-isolated electrical power to multiple, electricallyisolated, electrical switches.

In one or more embodiments, a laser power beaming system (which caninclude either the laser beam delivered wirelessly through free space,or delivered through an optical fiber) can deliver multiple,electrically isolated power outputs to power multiple electronicswitches with independent, floating voltages. In one or moreembodiments, if the optical power is delivered by optical fiber, theoptical fiber cable is a dielectric or non-conductive. Some existinghigh power laser fibers include a conductive wire or shell to indicatethat a fiber is plugged in and has not been broken; such cables are notpreferred unless there is an adequate gap in the conductive wire orshell to keep the transmitter electrically isolated from the receiverand to keep the power outputs of the receiver electrically isolated fromone another.

FIG. 1 is a laser power beaming system 8 according to an embodimentdisclosed herein. In FIG. 1, electrical power 10 (which could be directcurrent (DC) or alternating current (AC), for example from a standard120V AC outlet) energizes a laser power transmitter 12, which mayinclude one or more laser drivers and one or more lasers.

The optical output of the laser(s) is then coupled (often using optics,for example as shown in FIG. 2) into an optical transmission medium 14,generally either an optical fiber or free space, positioned at an outputof the laser power transmitter 12. In one or more embodiments, theoptical fiber is a light guide that constrains light, via total internalreflection, within, for example, a cylindrical path, which may include acircular or other shape cross section. Optical fibers are commonly usedin optical telecommunications networks, but are also used to deliverhigh power laser light from a laser to a working optic. In one or moreembodiments, the free space is an optically transparent orsemi-transparent medium for sending optical power. Examples of freespace include air or other gas, a vacuum, a liquid (e.g., water), and atransparent solid (e.g., a window).

A power receiver 16 receives the light via the transmission medium 14.In one or more embodiments, there is no conductive path between thepower receiver 16 and the laser power transmitter 12. In one or moreembodiments, optics (e.g., lenses, prisms) are provided at the powerreceiver 16 for conditioning the light, such as by shaping, splitting,reflecting, and/or refracting the light.

In one or more embodiments, the power receiver 16 includes photovoltaic(PV) modules (for example, as shown in FIGS. 3 and 4), which receive thelight and, in response, output electric power. A PV module is a set ofone or more photovoltaic (PV) cells which are electrically connected andproduce a single electrical output. The PV cells in PV modules may beoptionally connected to power management and distribution modules (akaPMADs), which might include maximum power point tracking (MPPT) and/orDC/DC converting and regulating electronics (for example, as shown inFIG. 3, and without PMADs in FIG. 4).

As defined herein, a receiver power leg is a PV module, along withmaximum power point tracking (MPPT) and/or DC/DC for converting andregulating electronics, which together may be referred to as a PMAD(Power Management and Distribution). In one or more embodiments, thepower receiver 16 includes one or more receiver power legs. The electricpower generated by the PV modules is provided to a set of drivers whichin turn uses the electric power to generate a drive signal that drivesthe electronic switches. Each PV module and all of the electronics, ifany, after it in the power flow direction (for example, an MPPT and/orDC/DC converter) are electrically isolated from the other PV modules andtheir electronics, such that the switches can float at differentvoltages relative to each other.

FIGS. 3 and 4 illustrate the power receiver 16 according to embodimentsdisclosed herein. The power receiver 16 is a converter that converts alight beam emitted from the laser power transmitter 12 into anelectrical signal for the drivers 18. The power receiver 16 includes PVmodules 32 that are each configured to receive the light emitted fromthe laser power transmitter 12 through the transmission medium 14, and,in response, output electric power. In one or more embodiments, theelectric power output from the PV modules is an electrical signal havingelectrical characteristics (e.g., amplitude, frequency, power level,etc.) corresponding to an electrical power signal received from theelectrical power 10. The electric power generated by the PV modules 32is provided to the set of drivers 18 which drives the electronicswitches 20. As discussed above, in one or more embodiments, each PVmodule and all of the electronics, if any, after it in the power flowdirection (for example, an MPPT and/or DC/DC converter) are electricallyisolated from the other PV modules and their electronics, such that theswitches 20 can float at different voltages relative to each other. Inone or more embodiments, the electrical power output terminals of thepower receiver 16 are electrically isolated from each other.

Electronic Switching elements may refer to one or more types oftransistors, such as FETs (e.g., MOSFET, JFET) and IGBTs, by way ofnon-limiting example.

In one or more embodiments, as shown in FIG. 3, the power receiver 16includes PMADs 34, and PV cells in the PV modules 32 are connected tothe PMADs 34. The PMADs 34 are connected to output terminals of thepower receiver 16. The PMADs 34 include maximum power point tracking(MPPT) and/or DC/DC converting and regulating electronics.

FIG. 4 is the power receiver 16 according to another embodimentdisclosed herein. In contrast to the embodiment shown in FIG. 3, thepower receiver 16 in FIG. 4 does not include PMADs 34, and the PV cellsin the PV modules 32 are directly connected to output terminals of thepower receiver 16. As discussed above, in one or more embodiments, eachPV module and all of the electronics, if any, are electrically isolatedfrom the other PV modules and their electronics, such that the switches20 can float at different voltages relative to each other. In one ormore embodiments, the electrical power output terminals of the powerreceiver 16 are electrically isolated from each other.

Returning to FIG. 1, a switch controller 22 sends the appropriatesignals to each of the drivers 18 so that the drivers 18 driveelectrical switching elements or switches 20 in the correct manner (forexample, at a desired time). The switch controller 22 includes one ormore processors, memory, and input/output connections for controllingdrivers connected to switches 20. Each of the drivers 18 is electricallycoupled to a respective switch 20, and is configured to control anoperating state of the respective switch 20 (e.g., drive the respectiveswitch to be in an open/on state or to be in a closed/off state). As anexample, the switches 20 may each be controlled to output asubstantially sinusoidal electrical waveform having a desired frequencyand amplitude, and each waveform may be offset in phase from waveformsgenerated by other switches 20 of the optically-isolated VFD. In one ormore embodiments, the switch controller 22 includes an input forreceiving control signals, and is configured to control the drivers 18to actuate a load based on the control signals.

The laser power transmitter 12 may include an electrical powerconverter, one or more laser drivers, one or more lasers, and a thermalmanagement system to regulate the temperature of the lasers, a lasercontroller, and optics to shape the light. The thermal management systemmay be a passive or an active system. An active system may include achiller or thermoelectric cooler.

The laser power transmitter 12 is a converter that converts anelectrical power signal received from the electrical power 10 into anoptical light beam. In some embodiments, the laser power transmitter 12includes one laser. FIG. 2 shows the laser power transmitter 12according to an embodiment disclosed herein. The laser power transmitter12 includes a laser controller 24 configured to control the laser 26 andthermal management system 25, the thermal management system 25configured to regulate a temperature of the laser power transmitter 12,an electronic (laser) driver 26 configured provide a driving signal tothe laser 28 to emit light, the laser 28 itself configured to emit lightin response to receiving the driving signal, and optics 30 to shape orotherwise condition the light (e.g., shaping and/or focusing, which maybe performed by reflecting and/or refracting the light) for transmissioninto the transmission medium 14 (or media in some implementations). Inone or more embodiments, the light emitted from the laser 28 has opticalcharacteristics (e.g., amplitude, frequency, modulation frequency, powerlevel, and the like) corresponding to an electrical power signalreceived from the electrical power 10. The laser light emitted by thelaser power transmitter 12, more specifically the laser 28, may be split(e.g., via optics) into separate beams before reaching the physicallyseparate PV modules, such that each PV module receives light (forexample, as shown in FIG. 5). Splitting may be performed in the laserpower transmitter, or from one fiber to many fibers (in cases whereoptical fiber is used), or may be performed in the power receiver.

FIG. 5 shows a laser light being split into separate beams according toan embodiment disclosed herein. The incident laser light 36 in FIG. 5may be from either free space or an optical fiber. In one or moreembodiments, the optical element 38 labeled “optical splitter” is areflecting element that splits the incident beam into a number ofseparate beams each directed in approximately radial directions. In oneor more embodiments, as shown in FIG. 5, the optical element 38 is anN-sided pyramidal mirror (where N is an integer greater than 1). Opticaldesigns other than a pyramidal mirror could be used instead to achievethe same effect. Although a single optical element is shown in FIG. 5,any number of optical elements may be used. In one or more embodiments,turning mirrors 40, which may be flat mirrors angled at roughly 45°relative to the incident light direction, are used to redirect the lightat roughly a 90° angle towards the PV modules 32. The turning mirrors 40may be controlled (e.g., by the switch controller 22) to appropriatelydirect or steer light to one or more corresponding PV modules 32. In oneembodiment, as shown in FIG. 5, the PV modules 32, the optical splitters38, and the turning mirrors 40 are positioned on a substrate 41, such asa Printed Circuit Board (PCB).

FIGS. 6A and 6B show embodiments of receiver optics, in a case where anoptical fiber is a light source (e.g., in a cases where the transmissionmedium 14 is an optical fiber).

FIG. 6A shows receiver optics according to an embodiment disclosedherein. In the embodiment shown in FIG. 6A, light emitted from the laserpower transmitter 12 is emitted via an optical fiber 42 (e.g., thetransmission medium 14 is an optical fiber), and a lens 44 or otheroptical element is used to collimate the divergent light from theoptical fiber 42. The optical splitter 38, which in this case isrepresented as an N-sided pyramidal mirror, splits the approximatelycollimated light out radially, towards PV modules 32 (for example, asshown in FIG. 5). In one or more embodiments, the lens 44 is included inthe power receiver.

FIG. 6B shows receiver optics according to another embodiment disclosedherein. In FIG. 6B, light emitted from the laser power transmitter 12 isemitted via an optical fiber 42 (e.g., the transmission medium 14 is anoptical fiber). However, in contrast to the embodiment shown in FIG. 6A,a lens is not used to collimate the divergent light from the opticalfiber 42. Instead, the light is transmitted to the optical splitter 38though free space. In this embodiment, the optical splitter 38 operatesto both split and shape (for example, by collimating) the lightreceived, in this example provided by a concave shape to each segment ofthe N-sided pyramidal mirror. By shaping the light, the optical element(shown as a lens) in FIG. 6A is eliminated, its functionality havingbeen incorporated into the optical splitter. While the example shownuses reflective methods, other methods of splitting the light could beused, for example refractive methods, or a combination of methods.

In one or more embodiments, the PV modules 32 are all on a singlePrinted Circuit Board (PCB) (or direct bonded copper (DBC), or other“board”), as shown, for example, in FIGS. 3 and 4. The individual PVcells may have encapsulant or other insulating material on theconnecting electrical wires to reduce the possibility of electricaldischarge or corona connecting to them. Each PV module is physicallyseparated from the other PV modules (and from the electrical wiring) bya distance adequate to prevent electrical arcing between the relativevoltages in the application, or other electrical interference. Thesingle PCB has multiple, electrically-isolated outputs.

In one or more embodiments, the laser power transmitter 12 includes morethan one laser. In these embodiments, the light emitted from anindividual laser may be directed to an individual PV module 32.

FIG. 7 shows the laser power transmitter 12 and the power receiver 16according to another embodiment disclosed herein. In the embodimentshown in FIG. 7, the laser power transmitter 12 includes a plurality oflasers 28, and the power receiver 16 includes a plurality of PV modules32. In one or more embodiments, a total number of lasers 28 in the laserpower transmitter 12 is equal to a total number of PV modules 32 in thepower receiver 16; and each of the lasers 28 transmit light onto arespective PV module 32. For example, as shown in FIG. 7, each of thetwo lasers 28 transmits light onto a respective PV module 32. Althoughtwo lasers and two PV modules are shown in FIG. 7, the laser powertransmitter 12 may include any number of lasers, and the power receiver16 may include any number of PV modules.

In one or more embodiments, the light travels directly from the laser tothe PV module—for example, in cases where the beam divergence, PV size,and laser-to-PV spacing is such that no significant amount of lightwould be wasted and a high degree of energy transfer is achieved (e.g.,greater than 95% optical efficiency). In another embodiment, the lightfrom the laser may be collimated or otherwise shaped by one or moreoptical elements in order to project the light such that no significantamount of light is wasted at each PV module.

In one or more embodiments, a plurality of lasers may be implementedsuch that each of the lasers correspond to a separate PV module. In someembodiments, each laser may have its own fiber to go to its own PVmodule. The laser light might travel directly from the laser to the PVmodule without additional optical elements. For example, FIG. 8A is alaser and a PV module according to an embodiment disclosed herein. Inthe embodiment shown in FIG. 8A, the laser 28 emits light directly fromthe laser 28 to the PV module 32. Optical elements are not positionedbetween the laser 28 and the PV module 32.

In one or more embodiments, one or more optical elements are used toshape the laser light (for example, collimating it). For example, FIG.8B is a laser and a PV module according to another embodiment disclosedherein. In the embodiment shown in FIG. 8B, the laser 28 emits lightfrom the laser 28, through an optical element 46 (e.g., the lens 44),and to the PV module 32. In one or more embodiments, the optical element46 collimates light transmitted from the laser 28.

In one or more embodiments, the laser power transmitter 12 and the powerreceiver 16 is jointly enclosed in a single housing. In some of theseembodiments, the housing and any other materials that create a physicalconnection from the transmitter to the receiver would be non-conductive(e.g., electrically insulating). The transmitter and receiver may besufficiently spaced apart to prevent electrical arcing or corona at theexpected operating conditions.

In one or more embodiments, light that has been split into multiplebeams impinge directly on PV modules 32 that are oriented to catch thelight, instead of relying on turning mirrors as shown, for example, inFIG. 5. In these embodiments, the PV modules 32 may be mounted on thecarrier board (e.g., PCB) such that the PV modules 32 have a surfaceoriented transversely (e.g., perpendicular) to a surface of the mainboard plane. FIG. 9 shows an example of this type of embodiment.

FIG. 9 shows a laser light being split into separate beams according toan embodiment disclosed herein. Similar to the embodiment shown in FIG.5, laser light 36 is directed towards the optical element 38, which thensplits the incident last light into a number of separate beams. However,in contrast to the embodiment shown in FIG. 5, turning mirrors are notused to redirect the separate beams on to the PV modules 32. Instead, PVmodules 32 are mounted on their own substrates 48 or sub-boards thatextend from the surface of the substrate 41 or PCB main board and thatare in turn mounted on the main board (PCB). In one or more embodiments,the substrate 41 extends in a first direction, and the substrates 48extend in a second direction transverse to the first direction.Accordingly, the split beams impinge directly on to the PV modules 32.

The PV modules 32 include one or more photovoltaic cells. In one or moreembodiments, a PV module 32 includes a single PV cell per module. Inanother embodiment, each of the PV modules 32 includes multiple PVcells. In one or more embodiments, the output voltage range of PV cellsmight be adequate to directly power a device, such as a driver andswitch. In one or more embodiments, the PV cell output might be managedby a Maximum Power Point Tracker (MPPT) to extract maximum power. In oneor more embodiments, the output (with or without an MPPT) of the PV cellis converted and/or regulated by a DC/DC converter to match the desiredelectrical characteristics (e.g., voltage level, frequency, waveform)for operating (e.g., powering) a device coupled to the driver and switch(e.g., VFD).

FIGS. 10A and 10B illustrate a laser power beaming system 8 according toanother embodiment disclosed herein. In this embodiment, control signalsfrom the switch controller 22 for all of the drivers 18 are multiplexedby a multiplexer 50 into a data stream that is transmitted using thelaser power transmitter 12 as discussed above by modulating the laser 28(for example, by varying the light intensity) in such a way that isdetectable at the power receiver 16 and can be decoded by ademultiplexer 52. In one or more embodiments, shown in FIG. 10A themultiplexer 50 selects a control signal from the control signals fromthe switch controller 22. The demultiplexer 52 then routes the controlsignals to each of the drivers 18. In one or more other embodiments,shown in FIG. 10B the multiplexer 50 selects a control signal from thecontrol signals from the switch controller 22. Multiple demultiplexers52 then each route a control signal to a respective driver 18. In one ormore different embodiments (not shown), multiple multiplexers 50 (eachhaving a laser) each select a control signal from the switch controller22. The multiple multiplexers 50 send their respective control signalsto multiple demultiplexers 52 that each route a control signal to arespective driver 18.

In other embodiments, if multiple lasers are used separately for eachreceiver power leg (as shown, for example, in FIG. 7), the controllerdata for a specific driver may be multiplexed with the power for thatspecific receiver power leg. In one or more embodiments, a receiverpower leg is a PV module, along with maximum power point tracking (MPPT)and/or DC/DC converting and regulating electronics, which together maybe referred to as a PMAD (Power Management and Distribution), if any,and the electrical power output terminal or connector. In one or moreembodiments, the power receiver 16 includes one or more receiver powerlegs.

FIGS. 11A and 11B show examples of the wiring for drivers and switchesfor the laser power beaming system 8.

FIG. 11A is a driver and a switch according to an embodiment disclosedherein. In FIG. 11A, two power receivers 16 are shown. One of the powerreceivers 16 is set or referenced to voltage level A, and the other ofthe power receivers 16 is set or referenced to voltage level B. In oneor more embodiments, the voltage level A and the voltage level B areequal to each other. In one or more embodiments, the voltage level A andthe voltage level B are different voltage levels. The power receivers 16provide power to independent channels within the driver 18 (which may bean IC), which each drive a separate electronic switch 20. The switchcontroller 22 provides one or more control signals to the driver 18 thatdetermines when each switch 20 is being turned on or off. In one or moreembodiments, the lower voltage from each of the power receivers 16(labeled with a “-” symbol in FIG. 11A) may be referenced to the lowervoltage side of the switch 20 that corresponds to that power receiver16. The load 54 may be any type of load, component, or deviceelectrically coupled to the switches 20. In one or more embodiments, theswitches 20 actuate and operate the load 54.

FIG. 11B is drivers and switches according to another embodimentdisclosed herein. In FIG. 11B, a possible configuration is shown for aninverter type application (for example, a variable frequency drive). Inthis embodiment, three “legs” of the inverter (each leg corresponding toone driver 18) operate at different voltages relative to each other, andso three electrically isolated power receivers 16 provide power for eachdriver (the switches and other connections, such as the switchcontroller inputs, are not shown in FIG. 11B but are similar to what isshown in FIG. 11A). Since the lower voltage end of each inverter leg allgo to the same voltage (in this case, the power receiver 16 labeled asVoltage B is referenced to this lower output voltage, and which may beground), a single power receiver 16 is provided to power the lowervoltage side of all three drivers.

Photovoltaic cells disclosed herein may be single junction, doublejunction, or higher-number multi-junction type of cells. The junctionscan be stacked vertically or arranged adjacent horizontally. The outputopen circuit voltage and maximum power point voltage of a PV cell isapproximately the respective voltage of a single junction multiplied bythe total number of junctions. The open circuit voltage of a singlejunction depends on the type of photovoltaic material and other designfactors, but may be in the range of 0.6V-1.2V in some applications.

The receiver power legs disclosed herein may be physically spaced apartfrom each other, and may also have encapsulant or other insulation.These features facilitate isolation between different receiver powerlegs and may prevent electrical arcing, corona, or other electromagneticinterference between the legs. In different applications, the differencein electric signals transmitted through separate receiver power legsdepends on the desired application. Voltage difference between legs maybe hundreds of volts, for example 220V, 500V, 1,000V, several thousandvolts, or other voltage differences.

The configuration of the VFD, such as the number of receiver power legs,may depend on the type of device to be connected to an output of theoptically-isolated drivers and switches. In some embodiments, the VFDmay be configured to operate smaller devices having a single input andthat consume less than one kilowatt of power (e.g., single phase motor).In some embodiments, the VFD may be configured to operate moresubstantial devices having a plurality of inputs and consuming greaterthan one kilowatt of power (e.g., three-phase motors).

In some embodiments, each receiver power legs may have voltage and/orcurrent sensors which may provide feedback to the switching controllerfor error correction, controlling timings between outputs, and the like.

Certain words and phrases used in the present disclosure are set forthas follows. The terms “include” and “comprise,” as well as derivativesthereof, mean inclusion without limitation. The term “or,” is inclusive,meaning and/or. The phrases “associated with” and “associatedtherewith,” as well as derivatives thereof in all grammatical forms, maymean to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, or the like. The term “controller”means any device, system, or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware, orsoftware, or some combination of at least two of the same. Thefunctionality associated with any particular controller may becentralized or distributed, whether locally or remotely. Additionally,reference to the term “figure” may actually refer to multiple figures,e.g., reference to FIG. 11 may refer to FIGS. 11A and 11B. Otherdefinitions of certain words and phrases may be provided within thispatent document. Those of ordinary skill in the art will understand thatin many, if not most instances, such definitions apply to prior as wellas future uses of such defined words and phrases.

Where one or more figures included in the present disclosure illustratesa data flow diagram, the illustrated process is a non-limiting processthat may be used by various embodiments. In this regard, each describedprocess may represent a module, segment, or portion of software code,which comprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that in someimplementations, the functions noted in the process may occur in adifferent order, may include additional functions, may occurconcurrently, and/or may be omitted.

Processors may include central processing units (CPU's),microcontrollers (MCU), digital signal processors (DSP), applicationspecific integrated circuits (ASIC), and the like. The processorsinterchangeably refer to any type of electronic control circuitryconfigured to execute programmed software instructions. The programmedinstructions may be high-level software instructions, compiled softwareinstructions, assembly-language software instructions, object code,binary code, micro-code, or the like. The programmed instructions mayreside in internal or external memory or may be hard-coded as a statemachine or set of control signals. According to methods and devicesreferenced herein, embodiments describe software executable by theprocessor and operable to execute certain ones of the method acts.

As known by one skilled in the art, a computing device has one or morememories, and each memory comprises any combination of volatile andnon-volatile computer-readable media for reading and writing. Volatilecomputer-readable media includes, for example, random access memory(RAM). Non-volatile computer-readable media includes, for example, readonly memory (ROM), magnetic media such as a hard-disk, an optical diskdrive, a floppy diskette, a flash memory device, a CD-ROM, and/or thelike. In some cases, a particular memory is separated virtually orphysically into separate areas, such as a first memory, a second memory,a third memory, and the like. In these cases, it is understood that thedifferent divisions of memory may be in different devices or embodied ina single memory. The memory in some cases is a non-transitory computermedium configured to store software instructions arranged to be executedby a processor.

The computing devices illustrated herein may further include operativesoftware found in a conventional computing device such as an operatingsystem or task loop, software drivers to direct operations through I/Ocircuitry, networking circuitry, and other peripheral componentcircuitry. In addition, the computing devices may include operativeapplication software such as network software for communicating withother computing devices, database software for building and maintainingdatabases, and task management software where appropriate fordistributing the communication and/or operational workload amongstvarious processors. In some cases, the computing device is a singlehardware machine having at least some of the hardware and softwarelisted herein, and in other cases, the computing device is a networkedcollection of hardware and software machines working together in aserver farm to execute the functions of one or more embodimentsdescribed herein. Some aspects of the conventional hardware and softwareof the computing device are not shown in the figures for simplicity.

Database structures, if any are present in the various embodiments, maybe formed in a single database or multiple databases. In some caseshardware or software storage repositories are shared amongst variousfunctions of the particular system or systems to which they areassociated. A database may be formed as part of a local system or localarea network. Alternatively, or in addition, a database may be formedremotely, such as within a “cloud” computing system, which would beaccessible via a wide area network or some other network.

Input/output (I/O) circuitry and user interface (UI) modules includeserial ports, parallel ports, universal serial bus (USB) ports, IEEE802.11 transceivers and other transceivers compliant with protocolsadministered by one or more standard-setting bodies, displays,projectors, printers, keyboards, computer mice, microphones,micro-electro-mechanical (MEMS) devices such as accelerometers, and thelike.

Buttons, keypads, computer mice, memory cards, serial ports, bio-sensorreaders, touch screens, and the like may individually or in cooperationbe useful to an operator of various embodiments. The devices may, forexample, input control information into the system. Displays, printers,memory cards, LED indicators, temperature sensors, audio devices (e.g.,speakers, piezo device, etc.), vibrators, and the like are all useful topresent output information to the operator of various embodiments. Insome cases, the input and output devices are directly coupled orotherwise electronically coupled to a processor or other operativecircuitry. In other cases, the input and output devices pass informationvia one or more communication ports (e.g., RS-232, RS-485, infrared,USB, etc.)

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges is also encompassed within the invention, subject to anyspecifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both ofthose included limits are also included in the invention.

Unless defined otherwise, the technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, a limitednumber of the exemplary methods and materials are described herein.

As used in the present disclosure, the term “module” refers to anapplication specific integrated circuit (ASIC), an electronic circuit, aprocessor and a memory operative to execute one or more software orfirmware programs, combinational logic circuitry, or other suitablecomponents (i.e., hardware, software, or hardware and software) thatprovide the functionality described with respect to the module.

Reference throughout this specification to “one embodiment” or “anembodiment” and variations thereof means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, the appearances of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout this specification are not necessarily all referring to thesame embodiment. Furthermore, the particular features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

The various embodiments described above can be combined to providefurther embodiments. These and other changes can be made to theembodiments in light of the above-detailed description. In general, inthe following claims, the terms used should not be construed to limitthe claims to the specific embodiments disclosed in the specificationand the claims, but should be construed to include all possibleembodiments along with the full scope of equivalents to which suchclaims are entitled. Accordingly, the claims are not limited by thedisclosure.

This application claims the benefit of priority to U.S. ProvisionalApplication No. 62/901,107 filed Sep. 16, 2019, the entirety of which isincorporated by reference herein.

1. A device comprising: a plurality of electrical switching elements; aplurality of drivers electrically coupled to the plurality of electricalswitching elements, the plurality of drivers configured to changeoperating states of the plurality of electrical switching elements; anda converter that includes a plurality of photovoltaic (PV) modulesconfigured to receive a plurality of light beams and convert theplurality of light beams into electrical signals for the plurality ofdrivers, the plurality of PV modules being electrically isolated fromone another.
 2. The device of claim 1, further comprising: a laser powertransmitter configured to: receive an electrical power signal; and inresponse to receiving the electrical power signal, transmit theplurality of light beams to the converter.
 3. The device of claim 2,wherein the plurality of light beams have optical characteristicscorresponding to the electrical power signal.
 4. The device of claim 2,further comprising: a transmission medium configured to transmit theplurality of light beams from the laser power transmitter to theconverter. 5-6. (canceled)
 7. The device of claim 1, wherein each memberof the plurality of PV modules includes at least one photovoltaic cellconfigured to convert light into electricity, and wherein the devicefurther includes a plurality of power management and distributionmodules electrically coupled to the plurality of PV modules.
 8. Thedevice of claim 1, further comprising: a laser power transmitterconfigured to receive an electrical power signal, and transmit a lightbeam in response to receiving the electrical power signal; and anoptical splitter configured to: receive the transmitted light beam; andsplit the transmitted light beam into the plurality of light beams. 9.(canceled)
 10. The device of claim 8, further comprising: an opticalelement configured to collimate the transmitted light beam.
 11. Thedevice of claim 8, wherein the optical splitter is configured tocollimate at least one member of the plurality of transmitted lightbeams. 12-16. (canceled)
 17. A power receiver, comprising: a pluralityof photovoltaic (PV) receiver legs, wherein: each PV receiver legincludes a PV module configured to convert an optical input to anelectrical output; and each member of the plurality of PV receiver legsis electrically isolated from each other member of the plurality. 18.The power receiver of claim 17, wherein each PV module comprises atleast one PV cell.
 19. The power receiver of claim 17, wherein at leastone PV module comprises a plurality of PV cells.
 20. The power receiverof claim 17, further comprising an optical element configured to:receive an incoming light beam; and direct at least a portion of thereceived incoming light beam onto a member of the plurality of PVreceiver legs.
 21. The power receiver of claim 20, wherein the opticalelement includes a beam splitter configured to direct a portion of theincoming light beam onto each member of the plurality of PV receiverlegs. 22-23. (canceled)
 24. The power receiver of claim 17, furthercomprising an optical fiber configured to direct an optical input towardone or more members of the plurality of PV receiver legs. 25-27.(canceled)
 28. The power receiver of claim 17, wherein at least one ofthe PV receiver legs includes a power management and distribution (PMAD)component.
 29. A power transmission system, comprising: the powerreceiver of claim 17; and a light source configured to provide anoptical input to the power receiver.
 30. The power transmission systemof claim 29, further comprising a transmission element configured toconduct the optical input from the light source to the power receiver.31. (canceled)
 32. The power transmission system of claim 29, furthercomprising a multiplexer configured to encode a control signal into theoptical input.
 33. The power transmission system of claim 32, furthercomprising a controller configured to create the control signal forencoding by the multiplexer.
 34. The power transmission system of claim32, wherein at least one member of the plurality of PV receiver legsincludes a demultiplexer configured to extract the encoded controlsignal from the electrical output of its PV module.
 35. The powertransmission system of claim 34, wherein each member of the plurality ofPV receiver legs includes a demultiplexer configured to extract theencoded control signal from the electrical output of its PV module. 36.The power transmission system of claim 35, wherein each demultiplexer isconfigured to identify a portion of the encoded control signal thatpertains to its own PV receiver leg.
 37. The power transmission systemof claim 34, further comprising a driver for controlling an electricalcomponent, wherein the driver is configured to receive the extractedcontrol signal from the demultiplexer and to use the received controlsignal to drive the electrical component. 38-48. (canceled)